The Cable Guy Strikes Again

Note to self: Write future post on the romantic notion that people with CRPS hang out in the garage, contemplating which gas-guzzling garden tool will best amputate the involved limb/s (leaf blower? string trimmer? pressure washer? maybe the SAW?). Better yet -- write that long-brewing post on the mythology of CRPS and suicide.

Baffling Chronic Pain Linked To Weird Rewiring Of Brain
ScienceDaily (Nov. 27, 2008) — Scientists peered at the brains of people with a baffling chronic pain condition and discovered something surprising. Their brains looked like an inept cable guy had changed the hookups, rewiring the areas related to emotion, pain perception and the temperature of their skin. [....]

This 3-dimensional graphic shows the abnormal rewiring of the

brain's right hemisphere in patients with complex region pain

syndrome. The orange path shows the location of gray matter

atrophy and damaged wiring in the anterior cingulate; blue

shows damage in the insula; green in the medial prefrontal cortex.

(Credit for image to Northwestern Univ.)

An even better layperson's overview, which also provides a context for the "discovery" (cough) above, can be found here:

At the time of these studies, researchers noted that although nerve damage is identifiable in CRPS-II, no research had yet shown actual nerve involvement in CRPS-I. In 2005, a research team from the Albany Medical College, New York, performed a microscopic, intricate analysis of skin specimens from the two Israelis.*** The examination showed that all sites in the skin where nerve endings were present, including hair follicles, blood vessels, sweat glands, and epidermis, were markedly abnormal. Results of the study, headed by Frank L. Rice, PhD, and Phillip J. Albrecht, PhD, of the Center for Neuropharmacology and Neuroscience at Albany Medical College, were presented in the article, "Pathologic Alterations of Cutaneous Innervation and Vasculature in Affected Limbs from Patients with Complex Regional Pain Syndrome," in the February 2006 issue of Pain, published by the International Association for the Study of Pain (IASP).

A team headed by Anne Louise Oaklander, MD, PhD, from Massachusetts General Hospital, Boston, a teaching and research hospital, was pursuing similar research. Since small-fiber nerve endings transmit pain messages and control skin color and temperature, and because damage to those fibers is associated with other painful conditions, the team hypothesized that these fibers also could be involved in CRPS-I.

Learned control of brain activity leads to improved pain control. This figure shows increases in brain activity in the anterior cingulate cortex, a brain region involved with the perception of pain. Increased control of this region led to corresponding changes in pain.

The team studied 18 CRPS-I patients and seven control patients with similar chronic pain known to be caused by arthritis. Skin biopsies from affected and unaffected areas of the CRPS-I patients' bodies showed that the density of small-fiber nerve endings was reduced by 25 to 30 percent in affected areas compared with unaffected areas. The arthritis patients did not have comparable nerve loss, indicating that the damage was specific to CRPS-I, not chronic pain in general. "These results support the hypothesis that CRPS-I is specifically associated with post-traumatic focal MDNI [minimal distal nerve injury] affecting nociceptive small-fibers," Oaklander stated in the study, "Evidence of Focal Small-Fiber Axonal Degeneration in Complex Regional Pain Syndrome-I (Reflex Sympathetic Dystrophy)," also published in Pain, February 2006. "This type of nerve injury will remain undetected in most clinical settings," she added.

***When I first read about this study performed on amputated limbs, I got the heebie-jeebies, and wrote (spewed?) the entry "Outsourcing."